Kernel Doom

UML driving a Doom dungeon

Dungeon is dynamic

Shell available to manipulate dungeon

Also Quake if hooks and/or source are available

Notes:

Finally, this is the killer app for UML.

This involves hooking a UML instance up to Doom so that the dungeon consists of kernel datastructures. They would be rooms, and pointers between them would be hallways.
You'd also have a shell that you could use to manipulate the kernel's data and the dungeon.